CN110549033A

CN110549033A - weather-resistant bridge steel Q690qE matched gas shielded welding wire and preparation method thereof

Info

Publication number: CN110549033A
Application number: CN201910866544.9A
Authority: CN
Inventors: 陈建雄; 吴江波; 杜伟
Original assignee: Sichuan West Metallurgy New Material Ltd By Share Ltd; China Railway Baoji Bridge Group Co Ltd
Current assignee: Sichuan West Metallurgy New Material Ltd By Share Ltd; China Railway Baoji Bridge Group Co Ltd
Priority date: 2019-09-12
Filing date: 2019-09-12
Publication date: 2019-12-10

Abstract

The invention discloses a gas shielded welding wire and a preparation method thereof, wherein the welding wire comprises the following components in percentage by weight: mn: 1.40% -1.80%; ni: 2.00% -3.00%; mo: 0.30% -0.65%; c is more than 0 and less than or equal to 0.10 percent; si is more than 0 and less than or equal to 0.60 percent; s is more than 0 and less than or equal to 0.010 percent; p is more than 0 and less than or equal to 0.010 percent; cr is more than 0 and less than or equal to 0.60 percent; cu is more than 0 and less than or equal to 0.35 percent; ti is more than 0 and less than or equal to 0.005 percent; v is more than 0 and less than or equal to 0.005 percent; the balance being Fe and other impurities. The preparation method comprises the steps of (a) preparing a wire rod according to the formula of a welding wire, and then roughly drawing the wire rod; (b) annealing the wire rod treated in the step (a) to remove an oxide layer on the surface of the wire rod; (c) carrying out secondary rough drawing on the wire rod processed in the step (b) to a certain specification; (d) and (c) finely drawing the wire rod processed in the step (c), plating copper on the surface of the wire rod, and winding the wire rod layer by layer. According to the gas shielded welding wire, through a reasonable welding process, the tensile strength of the weld metal is larger than 810MPa, the yield strength is larger than 755MPa, the mechanical property of the weld metal is close to that of a base metal, and the mechanical property requirement of bridge steel Q690qE is met.

Description

Weather-resistant bridge steel Q690qE matched gas shielded welding wire and preparation method thereof

Technical Field

the invention belongs to the technical field of welding materials, and particularly relates to a weather-resistant bridge steel Q690qE matched gas shielded welding wire and a preparation method thereof.

Background

With the rapid development of national economy and modern industry, welded steel bridges in China are widely applied to bridge construction with the unique advantages of light dead weight, large span, good earthquake resistance, easy repair and replacement and the like, and meanwhile, the traditional steel cannot meet the design and construction requirements due to the stricter service environment and performance requirements. The steel for the bridge has the characteristics of high strength, light structure, large thickness, excellent low-temperature impact toughness, excellent weldability, excellent corrosion resistance and the like.

with the first design and application of the weather-resistant bridge steel Q690qE in production practice, due to the requirements of complex space structure, high construction difficulty, high strength and high toughness, a matched welding material with excellent welding process and mechanical property is needed, the existing welding material for the weather-resistant bridge steel Q690qE is still incomplete, and no matched gas shielded welding wire exists except for a submerged arc welding wire and a flux-cored welding wire; the patent CN109175779A discloses a flux-cored wire for welding bridge steel Q500QE, the components of the flux-cored wire in the patent comprise boron nitride, Cr, Nb, Ni, Ti and other elements, the flux-cored wire is used for welding, the tensile strength of deposited metal is between 600 and 720MPa, the yield strength is between 540 and 580MPa, the flux-cored wire is matched with bridge steel Q500QE, but the strength of the deposited metal can not meet the requirement of mechanical property of bridge steel Q690 qe.

Patent CN109530967A discloses a submerged arc welding flux matched with Q690QE bridge steel, the welding flux comprises SiO2, MgO, Al2O3, CaF, CaO and the like, the welding flux has good welding process, a fluorine-alkali slag system is formed in the welding process, the tension of the surface of slag can be adjusted, the melting point of the slag is improved, the tensile strength of deposited metal obtained after welding is larger than 810MPa, and the yield strength is larger than 690 MPa. However, the flux is suitable for a submerged arc welding process, and has the defects of difficult construction and the like in a bridge structure with a complicated structure in the submerged arc welding process.

patent CN21021520025B discloses a gas shielded welding with tensile strength of 900MPa, the main alloy system of the gas shielded welding is Mn-Ni-Mo, the content of Ti element is high, the carbon equivalent of the welding wire is 0.7-0.85, the tensile strength of deposited metal after welding by the welding wire is 940-1010MPa, and the deposited metal is matched with steel of 900MPa, but related experiments show that the deposited metal after welding by the welding wire disclosed by the patent has poor weather resistance, poor welding performance and poor weld forming, and the deposited metal after welding by the welding wire is not matched with Q690QE bridge steel, so that the gas shielded welding is not suitable for Q690QE bridge steel.

patent CN104227264B discloses a solid wire for gas shielded arc welding of high strength steel, which can obtain a weld metal having appropriate strength and good toughness in a low temperature range in welding of 780-grade high strength steel, and has excellent welding workability, but the wire contains a large amount of Ti element, has poor weldability, is likely to generate spatter during welding, and has an unattractive weld.

In order to adapt to equal strength matching of Q690QE bridge steel, a special gas shielded welding wire for Q690QE bridge steel needs to be developed, so that higher requirements for the development of welding materials are met, the welding wire is suitable for a harsh service environment, and the overall strength of a bridge structure is ensured.

Disclosure of Invention

The invention aims to: the gas shielded welding wire for the Q690QE bridge steel is provided, the mechanical property of deposited metal formed by the welding wire after welding meets the requirement of the mechanical property of the Q690QE bridge steel, the tensile strength of the welding wire is larger than 810MPa, and the yield strength of the welding wire is larger than 755 MPa. The welded welding seam has the excellent performances of high strength, high toughness, good corrosion resistance, crack resistance and the like which are matched with the weather-resistant bridge steel Q690qE body, and can effectively improve the overall strength and service life of the novel weather-resistant steel bridge.

In order to achieve the purpose, the invention adopts the technical scheme that: a gas-shielded welding wire comprising, in weight percent: mn: 1.40% -1.80%; ni: 2.00% -3.00%; mo: 0.30% -0.65%; c is more than 0 and less than or equal to 0.10 percent; si is more than 0 and less than or equal to 0.60 percent; s is more than 0 and less than or equal to 0.010 percent; p is more than 0 and less than or equal to 0.010 percent; cr is more than 0 and less than or equal to 0.60 percent; cu is more than 0 and less than or equal to 0.35 percent; ti is more than 0 and less than or equal to 0.005 percent; v is more than 0 and less than or equal to 0.005 percent; the balance being Fe and other impurities.

wherein the carbon equivalent CE is [ (% C) + (% Mn)/6+ [ (% Cr) + (% Mo) + (% V) ]/5+ [ (% Ni) + (% Cu) ]/15, the carbon equivalent of the wire ranging from: 0.67-0.874.

Further, the gas shielded welding wire comprises the following components in percentage by weight: mn: 1.40 percent; ni: 2.00%%; mo: 0.30 percent; c: 0.10 percent; si: 0.60 percent; s: 0.010%; p: 0.010%; cr: 0.60 percent; cu: 0.35 percent; ti: 0.005 percent; v: 0.005 percent; the balance being Fe and other impurities. The carbon equivalent thereof was 0.67.

Further, the gas shielded welding wire comprises the following components in percentage by weight: mn: 1.80 percent; ni: 3.00 percent; mo: 0.65 percent; c: 0.10 percent; si: 0.60 percent; s: 0.010%; p: 0.010%; cr: 0.60 percent; cu: 0.35 percent; ti: 0.005 percent; v: 0.005 percent; the balance being Fe and other impurities. The carbon equivalent of the wire is 0.874.

further, after the welding wire is used for welding a base material of bridge steel Q690qE, deposited metal is formed and comprises the following component C in percentage by mass: 0.047% -0.086%, Mn: 1.23% -1.71%, Si: 0.26% -0.54%, Ni: 1.65% -2.77%, Mo: 0.27% -0.57%, Ti: 0.0010% -0.0042%, S: 0.003% -0.0085%, P: 0.0026% -0.01%, Cr: 0.36% -0.54%, Cu: 0.102% -0.32%, V: 0.0013 to 0.0048 percent, and the balance of Fe and impurities.

Further, after the welding wire is used for welding a base material of bridge steel Q690qE, deposited metal is formed and comprises the following components in percentage by mass: c: 0.064% -0.066%, Mn: 1.41% -1.71%, Si: 0.26% -0.36%, Ni: 2.68% -2.77%, Mo: 0.44% -0.55%, Ti: 0.0020% -0.0030%, S: 0.0045% -0.006%, P: 0.009% -0.0091%, Cr: 0.40% -0.42%, Cu: 0.102% -0.12%, V: 0.0023% -0.0043%; the balance being Fe and impurities.

The formed deposited metal satisfies the following mass fractions:

26.01 (% Cu) +3.88 (% Ni) +1.20 (% Cr) +1.49 (% Si) +17.28 (% P) -7.29 (% Cu) x (% Ni) -9.10 (% Ni) x (% P) -33.39 (% Cu) ², wherein I is the weather resistance index, and (% Cu), (% Ni), (% Cr), (% Si), and(% P) represent the contents of Cu, Ni, Cr, Si, and P in mass%, respectively.

The welding wire designed by the invention is a weather-resistant bridge steel Q690qE gas shielded welding wire which takes Mn-Ni-Mo as a main alloy system, adopts C, Mn, Si, Cu, Cr and Ti elements to strengthen the alloy and strictly controls impurity elements such as welding wire S, P, and comprises the following components in the gas shielded welding wire:

in the invention, the carbon, manganese and silicon elements are added as alloy elements, and the alloy elements have the functions of not only deoxidizing in the welding process, but also strengthening the structure of a weld joint and ensuring the mechanical property of deposited metal. Particularly, the tensile strength is increased along with the increase of the content of carbon and manganese in the welding wire. However, the toughness of the welding wire is reduced along with the increase of the contents of carbon and manganese, through the research of the inventor of the application, the content of manganese in the welding wire is controlled to be 1.40-1.80%, the content of silicon is controlled to be 0< Si < 0 > and less than or equal to 0.60%, the tensile strength and the toughness of the welding wire can reach a better range, and the comprehensive performance of the welding wire is ensured.

The contents of sulfur and phosphorus are strictly controlled to be 0< S < 0.010% and 0< P < 0.010% respectively, S, P is an inevitable impurity element in the steelmaking process, if the content of the welding wire is too high, the impact toughness of deposited metal is influenced, and cracks are easy to generate, and through research by the inventor of the invention, the content of P, S two elements in the welding wire of the invention is controlled to be less than 0.010%, so that the impact toughness of the deposited metal after welding of the welding wire is good, and the deposited metal is not easy to generate cracks.

In the welded deposited metal, chromium elements and carbon form carbides which are dispersed and distributed, the carbides are uniformly distributed in the deposited metal and are expressed as a large number of granular precipitates with regular shapes, and the uniformly distributed granular precipitates are used as hard points among deposited metal crystals and can effectively improve the strength of a welding seam. In the welding process, the chromium element in the welding wire is also beneficial to improving the content of acicular ferrite, reducing proeutectoid ferrite and playing a role in refining ferrite grains, the finer the crystal of the ferrite grains is, the better the toughness of deposited metal is, but the inventor researches show that when in the welding wire of the application, a small amount of Cr can expand a gamma region and reduce the gamma → alpha phase transition critical temperature, so that the gamma → alpha phase transition is carried out at a lower temperature, the refining effect of phase transition grains is necessarily enhanced, when the content of Gr is more than 0.60 percent, the acicular ferrite in the deposited metal can be rapidly reduced in the welding process, the coarse crystal region and the fine crystal region of the deposited metal are subjected to microstructure homogenization, ferrite/carbide aggregate is formed in an incomplete phase transition region, although the hardness, yield point and tensile strength of a welding seam are improved, but the toughness of the deposited metal is seriously deteriorated, affecting the overall properties of the deposited metal. Therefore, the content of the chromium element in the welding wire is controlled to be 0< Cr < 0.60%, so that the strength and the toughness of the welding seam are improved. Preferably, the content of chromium is controlled to 0.4% to 0.6%, and within this range, the balance between the toughness and the strength of the welding wire is optimized.

The nickel element can strengthen ferrite and refine pearlite, the nickel element can effectively improve the strength of the weld metal, and the nickel with the content of 2.00-3.00% and the content of 0< Cr < 0.60% have synergistic effect to improve the strength of the weld metal. 2.00 to 3.00 percent of nickel is added into the welding wire, thereby improving the resistance of steel to fatigue, reducing the sensitivity of steel to gaps, reducing the low-temperature brittle transition temperature of steel, and improving the corrosion resistance of weld metal to acid, alkali, atmosphere, salt and the like. The research of the inventor finds that Ni can be dissolved in gamma-Fe in an unlimited solid mode, a gamma phase region is expanded, the gamma → alpha phase transition critical temperature is reduced, and the gamma → alpha phase transition is carried out at a lower temperature, so that the effect of strengthening the refinement of phase transition grains is achieved, when the Ni is lower than 2.00%, eutectoid ferrite in a welding seam is higher, acicular ferrite is less, and the hardness, yield point, tensile strength, welding seam toughness and the like of the welding seam are lower; when the nickel content is higher than 3.00%, elements such as Ni and Mn are not properly matched, so that the weld joint is seriously embrittled, and the toughness is greatly reduced.

0.30 to 0.65 percent of molybdenum can effectively improve the metal strength of the welding seam and refine grains. Mo is a medium-strong carbide forming element, a proper amount of Mo can reduce a gamma phase region, and the Mo exists in a form of solid solution in a matrix or carbide, so that the Mo strongly inhibits P transformation and also has an inhibiting effect on formation of pro-eutectoid ferrite. With the increase of Mo content in the welding seam, eutectoid ferrite in the welding seam is gradually reduced, acicular ferrite is gradually increased and then reduced, common grains in a coarse crystal area and a fine crystal area are refined, ferrite and carbide clusters are formed in an incomplete phase change area, the strength and the like of the welding seam are improved, the content of Mn element is matched, and 0.30% -0.65% of Mo is most beneficial to toughness.

The C element in the wire is one of important elements determining the weldability of the material, and a small amount of C reacts with alloy elements to generate dispersed carbides, thereby strengthening the base metal, and if the carbides exist in a flake form, the toughness of the weld is deteriorated. The proper C content is beneficial to improving the cleavage fracture resistance and can improve the metal toughness of the welding seam. The addition of Mn element can perform single deoxidation and also can perform combined deoxidation with Si, and a replacement reaction is performed in the welding seam melting process, so that the formation of iron sulfide inclusions which are easy to cause thermal cracking is prevented, and the ferrite grains and carbides of the microstructure of the welding seam are deeply promoted to be refined, thereby the toughness of the welding seam is better. Along with the increase of Mn content in a welding seam, the size of original austenite crystal grains is reduced, the size of a fine crystal area is refined, pro-eutectoid ferrite is obviously reduced, side plate bar ferrite is slightly reduced, the refined acicular ferrite is almost linearly increased, the yield strength and the tensile strength of the welding seam are increased by about 10MPa every 0.1 percent of Mn is added in the welding seam, and the impact toughness in a post-welding and stress-relief state is optimal when 1.40 to 1.80 percent of Mn is added. When Mn-Si exists in the welding seam at the same time, the welding seam structure and the performance are greatly influenced, and the phase change temperature during continuous cooling can be reduced and the structure is refined along with the increase of the content of Mn-Si. While other components in the weld remain unchanged, as Si increases at low Mn and high Mn, acicular ferrite increases and the aspect ratio of acicular ferrite changes in the weld, increasing secondary phase particles are captured, and hardness and mechanical properties increase nonlinearly, but notch toughness deteriorates and the deterioration results depend on the Mn content. When the optimum content of Mn is selected, the Si content should not exceed 0.60%.

the titanium and vanadium in the welding wire have the functions of solidifying the structure, stabilizing the electric arc, deoxidizing, fixing nitrogen and the like. The copper has the prominent effect of improving the atmospheric corrosion resistance of common low-alloy steel, particularly the copper is matched with phosphorus for use, and the strength and yield ratio of the steel can be improved by adding the copper.

In the invention, the preparation method of the welding wire is provided:

(a) Preparing a wire rod according to a formula of a welding wire, and then roughly drawing the wire rod;

(b) annealing the wire rod treated in the step (a) to remove an oxide layer on the surface of the wire rod;

(c) Carrying out secondary rough drawing on the wire rod processed in the step (b) to a certain specification;

(d) And (c) finely drawing the wire rod processed in the step (c), plating copper on the surface of the wire rod, and winding the wire rod layer by layer.

Further, in the step (a), the diameter of the wire rod after rough drawing is 4.2 mm.

Further, the rough drawing and the secondary rough drawing process comprise the steps of coating boron on the surface of the wire rod by adopting boron liquid with certain concentration, drying at the temperature of 150-200 ℃, matching with drawing powder, and drawing for 3-5 times. Wherein the content of borax in the boron liquid is 450-540g/L, and the temperature of the boron liquid is 96-100 ℃.

Further, the annealing treatment process comprises the following steps:

a temperature rising stage: heating to 650-700 ℃ at a heating rate of not more than 150 ℃/h, and preserving heat for 8-12 h;

A first cooling stage: cooling to below 350 ℃ along with the furnace, wherein the cooling speed is not more than 30 ℃/h;

And a second cooling stage: rapidly cooling to below 150 ℃; and (4) discharging.

Further, in the temperature rising stage and the first cooling stage, nitrogen with the purity of 99.99 percent is introduced at the speed of 3.2-6m 3/h.

Further, a well annealing furnace or a hood annealing furnace is used for annealing treatment.

Furthermore, the copper plating solution used in the copper plating process is 25-45g/L copper sulfate solution, and the copper plating speed is 4.0-5.0 m/s.

the content of borax in the boron liquid is 450-540g/L, and the temperature of the boron liquid is 96-100 ℃.

The copper plating solution used in the copper plating process is 25-45g/L copper sulfate solution, and the copper plating speed is 4.0-5.0 m/s.

The wire rod prepared by the components of the welding wire provided by the invention has high tensile strength and poor plasticity, and in the cold drawing process of the wire rod, the die consumption is high, the wire is easy to break, the production efficiency is low, the drawing process is not smooth, and the produced welding wire is easy to explode due to too high strength and is difficult to feed in the welding process. Therefore, in order to ensure smooth production of the welding wire and the quality of the finished welding wire, the wire rod is subjected to primary annealing treatment after the original wire rod is drawn to phi 4.2 mm.

The annealing process adopted by the invention is a recrystallization annealing process, and because the Mn-Ni-Mo alloy has solid phase change (recrystallization) during balanced heating and cooling, the alloy undergoes one-time phase change recrystallization during heating and cooling respectively during the process of slowly heating, preserving heat and cooling the wire rod in the annealing furnace, thereby completing the whole recrystallization annealing process, enhancing the plasticity of the wire rod, reducing the hardness and improving the drawing performance of the wire rod during the annealing process. Good conditions are provided for the subsequent secondary rough drawing and fine drawing.

The wire rod can be softened by high-temperature annealing for a long time, and the wire rod is softened in a controllable range by designing and optimizing annealing process parameters, so that the hardness is reduced, and good drawing plasticity is obtained.

The research of the inventor of the application shows that the annealing temperature of the wire rod is controlled at 650-700 ℃, and the strength and the toughness of the welding wire can be coordinated at a proper annealing temperature under the condition of not influencing the welding performance of the welding wire; when the annealing temperature is lower than 650 ℃, the wire rod cannot be completely austenitized, so that the annealing is insufficient, the internal stress of the wire rod is not completely eliminated, the phase change recrystallization is incomplete, the tensile strength and hardness of the annealed wire rod are still high, the plasticity is low, and the wire rod is not beneficial to drawing. When the annealing temperature is higher than 700 ℃, although the internal structure of the wire rod is fully austenitized, the internal stress is eliminated, the excessive temperature causes the growth of primary carbides, large-size carbide particles form internal defects, the drawing plasticity of the wire rod is damaged, and micro-cracks are generated in the drawing process to cause drawing brittle failure.

In addition to the change of the annealing heating temperature to the plasticity of the wire rod, the annealing heat preservation time is another important factor for ensuring the plasticity of the annealed wire rod, the heat preservation time is 8-12h, the wire rod matrix is fully austenitized, the stress is eliminated, and the wire rod belongs to complete annealing, so that the hardness and the tensile strength of the wire rod are not greatly changed, however, after the heat preservation time exceeds 12h, primary carbide particles are coarsened, and the plasticity of the wire rod is reduced. However, in order to ensure the homogenization of the annealing wire rod, the annealing heat preservation time is not easy to be too short, and the annealing heat preservation time is preferably between 8h and 12h in the invention.

due to the adoption of the technical scheme, the invention has the beneficial effects that:

According to the gas shielded welding wire, through a reasonable welding process, the welding wire is welded on a Q690qE base metal, the chemical components and the structure of the formed welding seam metal reach the best, the tensile strength of the welding seam metal is larger than 810MPa, the yield strength is larger than 755MPa, the mechanical property of the welding seam metal is close to that of the base metal, and the mechanical property requirement of bridge steel Q690qE is met; the welding process performance of the welding wire is excellent, splashing is small during welding, a welding seam is attractive and fine in forming, the edge of the welding seam is smooth in transition, the welding seam has good metal luster, the content of weld metal S, P is low, and the mechanical properties such as tensile strength, impact value, bending property, crack resistance and the like are excellent.

Drawings

FIG. 1 is a 100-fold metallographic view of a deposited metal according to example 1;

FIG. 2 is a 500-fold metallographic view of a deposited metal according to example 1;

Detailed Description

The gas shielded welding wire is mainly used for welding weather-resistant bridge steel Q690qE and steel with high strength and high toughness at the same level, and is smelted and rolled in a steel mill. The wire belongs to medium-high carbon steel wire, has the characteristics of high technical content, good economic benefit and the like, and meanwhile, the wire needs to be further drawn to produce the welding wire, so that the requirements on the smelting process and the billet quality used by a steel mill and the inclusions, sulfides and the like in steel are very strict, and when the original wire rod is prepared, the original wire rod of the welding wire is obtained through related process methods such as a blast furnace → molten iron pre-desulfurization → electric furnace refining → continuous casting → rolling and the like.

TABLE 1 mass fraction of each component of the welding wire

Example 1:

Preparing an original wire rod by a preparation method in the prior art according to the components of the original wire rod; in the embodiment, the original wire rod comprises the following components in percentage by weight:

C: 0.078%; mn: 1.78 percent; si: 0.37 percent; ni: 2.75 percent; mo: 0.45 percent; ti: 0.0024%, S: 0.004%; p: 0.010%; cr: 0.42 percent; cu: 0.02 percent; v: 0.0048%; the balance being Fe and other impurities.

The welding wire is prepared by the following method:

(a) preparing a wire rod according to the formula, matching with drawing powder, and roughly drawing the wire rod until the diameter is 4.2 mm; in the course of the rough drawing process,

(b) annealing the wire rod treated in the step (a), and removing an oxide layer on the surface of the wire rod through an abrasive belt machine, wherein the operational parameters of the abrasive belt machine are as follows: the starting frequency of the main shaft is 12-24HZ, and the frequency of the main shaft motor is less than or equal to 48 HZ.

(c) And (c) carrying out secondary rough drawing on the wire rod processed in the step (b) until the diameter of the wire rod is 2.4 mm.

(d) and (c) carrying out fine drawing on the wire rod processed in the step (c) until the diameter is 1.2mm, plating copper on the surface, and carrying out layer winding to obtain the gas shielded welding wire.

In this embodiment, the rough drawing process includes coating boron on the surface of the wire rod with a boron solution, drying the boron on the surface of the wire rod at a high temperature of 150 ℃, and drawing the wire rod for 3-5 times by using a special calcium-based drawing powder for a special welding wire, which is prepared by a self-developed ratio. Wherein, the content of borax in the boron liquid is 461g/L, and the temperature of the boron liquid is 98 ℃ during boron coating. The surface of the wire rod is coated with boron, so that a protective layer is formed on the surface of the wire rod, and the borax layer can protect the wire rod and the die in the drawing process because the borax has certain heat resistance, so that the wire rod and the die are prevented from being damaged by heat generated by high-speed drawing.

In the embodiment, after the fine drawing, copper is plated on the surface of the wire rod, the copper plating solution is 25g/L copper sulfate solution, the copper plating speed is 4.0m/s, and the reaction time of the welding wire in a copper plating tank is controlled by reasonably controlling the copper plating speed, so that the final copper content of the welding wire is 0< Cu and less than or equal to 0.50%.

In this embodiment, the annealing process includes:

The wire rod after rough drawing is placed in a well type annealing furnace, nitrogen with the purity of 99.99% is introduced into the well type annealing furnace at the speed of 3.2m ³/h continuously, the temperature of the original wire rod is raised to 650 ℃ at the heating rate of 100 ℃/h, then the wire rod is kept warm for 12h under the nitrogen atmosphere, after the wire rod is kept warm for 12h, the wire rod is cooled to 350 ℃ along with the furnace, and the cooling rate is 30 ℃/h, wherein in the processes of heating, keeping warm and cooling along with the furnace, nitrogen is always introduced into the well type annealing furnace, and the wire rod is always under the protection of the nitrogen atmosphere, so that the components in the wire rod are prevented from reacting with oxygen in the air to influence the components of the wire rod in the processes of heating and cooling.

Cooling to 350 ℃ along with the furnace, and then starting an air cooler for ventilation to ensure that the temperature of the wire rod is rapidly reduced to 150 ℃; discharging and naturally cooling.

The composition of the wire produced by the method of this example was:

C: 0.080%; mn: 1.72 percent; si: 0.33 percent; ni: 2.84 percent; mo: 0.40 percent; ti: 0.0020%, S: 0.005 percent; p: 0.008 percent; cr: 0.38 percent; cu: 0.12 percent; v: 0.005 percent; the balance being Fe and other impurities (Cu content includes the copper plating on the surface of the wire).

the gas shielded welding wire of the present example was applied to a base material having a thickness of 20mm, wherein the base material composition C: 0.072; 0.15 of Si; mn is 1.49; s is 0.001; p is 0.007; 0.011 Ti; v is 0.007; the balance of Fe and impurities; performing a multilayer multi-channel gas-shielded deposition welding experiment, wherein the protective atmosphere is 80% Ar + 20% CO2, the welding current is 260-280A, the arc voltage is 24-31V, and the inter-channel temperature is not more than 150 ℃;

The detected deposited metal of the welding seam comprises the following chemical components:

0.066% of C, 1.41% of Mn, 0.26% of Si, 2.75% of Ni, 0.55% of Mo, 0.0023% of Ti, 0.0045% of S, 0.0091% of P, 0.40% of Cr, 0.102% of Cu, 0.0043% of V, and the balance of iron and impurity elements.

Example 2:

C: 0.069%; mn: 1.70 percent; si: 0.39 percent; ni: 2.72 percent; mo: 0.57 percent; ti: 0.0027 percent; s: 0.0037%; p: 0.009%; cr: 0.40 percent; cu: 0.02 percent; v: 0.0033%; the balance being Fe and other impurities.

The welding wire is prepared by the following method:

(a) Preparing a wire rod according to the formula, matching with drawing powder, and roughly drawing the wire rod until the diameter is 4.2 mm;

(c) And (c) carrying out secondary rough drawing on the wire rod processed in the step (b) until the diameter of the wire rod is 2.34 mm.

In this embodiment, the rough drawing process includes coating boron on the surface of the wire rod with a boron solution, drying the boron on the surface of the wire rod at a high temperature of 180 ℃, and drawing the wire rod for 3-5 times by using a special calcium-based drawing powder for a special welding wire which is prepared by a self-developed ratio. Wherein, the content of borax in the boron liquid is 500g/L, and the temperature of the boron liquid is 100 ℃ when boron is coated. The surface of the wire rod is coated with boron, so that a protective layer is formed on the surface of the wire rod, and the borax layer can protect the wire rod and the die in the drawing process because the borax has certain heat resistance, so that the wire rod and the die are prevented from being damaged by heat generated by high-speed drawing.

In the embodiment, after the fine drawing, copper is plated on the surface of the wire rod, the copper plating solution is 30g/L copper sulfate solution, the copper plating speed is 4.0m/s, and the reaction time of the welding wire in a copper plating tank is controlled by reasonably controlling the copper plating speed, so that the final copper content of the welding wire is 0< Cu and less than or equal to 0.50%.

In this embodiment, the annealing process includes:

the method comprises the steps of placing a roughly drawn wire rod in a well type annealing furnace, introducing nitrogen with the purity of 99.99% into the well type annealing furnace at the speed of 4m ³/h continuously, raising the temperature of the original wire rod to 680 ℃ at the heating rate of 130 ℃/h, then preserving the temperature of the wire rod for 10h in the nitrogen atmosphere, cooling the wire rod to 350 ℃ along with the furnace after preserving the temperature for 10h, and cooling at the cooling rate of 30 ℃/h, wherein the nitrogen is always introduced into the well type annealing furnace in the processes of heating, preserving the temperature and cooling along with the furnace, and the wire rod is always protected by the nitrogen atmosphere so as to prevent components in the wire rod from reacting with oxygen in the air to influence the components of the wire rod in the processes of heating and cooling.

Cooling to 350 deg.C, ventilating with air cooler to rapidly lower the temperature of the wire rod to 150 deg.C, and naturally cooling.

The composition of the wire produced by the method of this example was:

C: 0.065%; mn: 1.69 percent; si: 0.37 percent; ni: 2.74 percent; mo: 0.49 percent; ti: 0.0031%; s: 0.004%; p: 0.010%; cr: 0.38 percent; cu: 0.21 percent; v: 0.0023%; the balance being Fe and other impurities (Cu content includes the copper plating on the surface of the wire).

Carrying out a multilayer multi-pass gas shielded vertical upward cladding welding experiment on a test plate (low-alloy high-strength steel) with the thickness of 20mm by using the gas shielded welding wire disclosed by the embodiment, wherein the protective atmosphere is 80% Ar + 20% CO2, the welding current is 140-160A, the arc voltage is 18-25V, and the inter-pass temperature is not more than 140 ℃;

C: 0.067%; mn: 1.71 percent; si: 0.33 percent; ni: 2.68 percent; mo: 0.44%; ti: 0.0030%; s: 0.006%; p: 0.009%; cr: 0.40 percent; cu: 0.12 percent; v: 0.0023 percent of iron and impurity elements in balance.

example 3:

Preparing an original wire rod by a preparation method in the prior art according to the components of the welding wire; in the embodiment, the original wire rod comprises the following components in percentage by weight:

C: 0.074%; mn: 1.67 percent; si: 0.36 percent; ni: 2.78 percent; mo: 0.57 percent; ti: 0.0025 percent; s: 0.003%; p: 0.011 percent; cr: 0.4 percent; cu: 0.022%; v: 0.005 percent; the balance being Fe and other impurities.

The welding wire is prepared by the following method:

(a) preparing a wire rod according to the formula, matching with drawing powder, and roughly drawing the wire rod until the diameter is 4.23 mm;

(c) And (c) carrying out secondary rough drawing on the wire rod processed in the step (b) until the diameter of the wire rod is 2.2 mm.

In this embodiment, the rough drawing process includes coating boron on the surface of the wire rod with a boron solution, drying the boron on the surface of the wire rod at a high temperature of 200 ℃, and drawing the wire rod for 3-5 times by using a special calcium-based drawing powder for a special welding wire which is prepared by a self-developed ratio. Wherein, the content of borax in the boron liquid is 540g/L, and the temperature of the boron liquid is 100 ℃ during boron coating. The surface of the wire rod is coated with boron, so that a protective layer is formed on the surface of the wire rod, and the borax layer can protect the wire rod and the die in the drawing process because the borax has certain heat resistance, so that the wire rod and the die are prevented from being damaged by heat generated by high-speed drawing.

in the embodiment, after the fine drawing, copper is plated on the surface of the wire rod, the copper plating solution is 40g/L copper sulfate solution, the copper plating speed is 5.0m/s, and the reaction time of the welding wire in a copper plating tank is controlled by reasonably controlling the copper plating speed, so that the final copper content of the welding wire is 0< Cu and less than or equal to 0.50%.

In this embodiment, the annealing process includes:

The method comprises the steps of placing a roughly drawn wire rod in a well type annealing furnace, introducing nitrogen with the purity of 99.99% into the well type annealing furnace at the speed of 6m ³/h continuously, raising the temperature of the original wire rod to 700 ℃ at the heating rate of 150 ℃/h, then preserving the heat of the wire rod for 8h under the nitrogen atmosphere, cooling the wire rod to 350 ℃ along with the furnace after preserving the heat for 8h at the cooling rate of 30 ℃/h, wherein the nitrogen is always introduced into the well type annealing furnace in the processes of heating, preserving the heat and cooling along with the furnace, and the wire rod is always protected by the nitrogen atmosphere so as to prevent components in the wire rod from reacting with oxygen in the air to influence the components of the wire rod in the processes of heating and cooling.

The composition of the wire produced by the method of this example was:

C: 0.070%; mn: 1.65 percent; si: 0.37 percent; ni: 2.80 percent; mo: 0.54 percent; ti: 0.0022%; s: 0.005 percent; p: 0.008 percent; cr: 0.38 percent; cu: 0.23 percent; v: 0.0036%; the balance being Fe and other impurities (Cu content includes the copper plating on the surface of the wire).

Carrying out a multilayer multi-pass gas shielded welding vertical up butt welding experiment on a test plate (low-alloy high-strength steel) with the thickness of 54mm by using the gas shielded welding wire disclosed by the embodiment, wherein the protective atmosphere is 80% Ar + 20% CO2, the welding current is 140-160A, the arc voltage is 18-25V, and the inter-pass temperature is not more than 140 ℃;

0.064% of C, 1.48% of Mn, 0.36% of Si, 2.77% of Ni, 0.53% of Mo, 0.0020% of Ti, 0.005% of S, 0.009% of P, 0.42% of Cr, 0.12% of Cu, 0.0033% of V, and the balance of iron and impurity elements.

In other embodiments of the present invention, the method for removing the oxide layer on the surface of the wire rod may be other polishing methods in the prior art, for example, manual polishing by sand paper, acid washing, etc.

examples 4 to 8

welding wires were prepared by the same preparation method as in example 1, with the composition of the welding wires of examples 4 to 8 in table 1 adjusted for the formulation of the original wire rod.

Comparative example: welding wires of comparative examples were prepared according to the contents of the components in the following Table 2

TABLE 2 comparative examples 1-8 welding wire components mass fraction

comparative example 7: the composition of the welding wire of example 4 in the specification of patent CN21021520025B is selected as the welding wire of comparative example 7.

Comparative example 8: the composition of the welding wire of example 5 in the specification of patent CN104227264B was selected as the welding wire of comparative example 8.

experimental example:

the welding wires of the above examples 4 to 8 and comparative examples 1 to 8 were welded to the base material having the same composition by the same welding process as in example 1.

the deposited metals of examples 1 to 8 were subjected to a tensile test (butt joint tensile test), an impact test, and a bending test, and the mechanical properties of the deposited metals of the examples were obtained, and the results are shown in table 3 below:

TABLE 3 deposited metal Properties after welding of examples 1-8 and comparative examples 1-8 with welding wire

From examples 1 to 8 and comparative examples 1 to 8 described above, the bending angle in the bending test was 180 ° and the bending diameter was 4T. In examples 1, 4 and 7 and comparative examples 1, 4 and 7, the mechanical properties of the deposited metal were measured in a 20mm flat welded state of the test panel, in examples 2, 5 and 8 and comparative examples 2, 5 and 8, in a 20mm vertical welded state of the test panel, and in examples 3 and 6 and comparative examples 3 and 6, in a butt joint state of a 54mm vertical thick plate, the mechanical properties of the butt joint were measured.

From the above table 3, it can be seen that the deposited metal after welding by the welding wire of examples 1 to 8 of the present invention has excellent tensile strength and yield strength, and matches with the mechanical properties of the bridge steel Q690qE, and in examples 1 to 8, the welded base metal is qualified after the bending test, and the bending test is as follows: the parent metal is 20mm thick and is subjected to surface bending and back bending, D is 4T, the bending angle alpha is 180 degrees, the parent metal is 52mm thick and is subjected to side bending, D is 4T, the bending angle alpha is 180 degrees, T is the thickness of the sample, and D is the diameter of a bending center. Judging the standard of the bending test result: no crack is generated after bending or the crack length is 3mm less, so the product is qualified; the cracking length of more than 3mm is unqualified. The mechanical properties and butt joint performance indexes of the cladding metals of the welding seams of the embodiments 1 to 8 show that the welding seam welded by the gas shielded welding wire has good mechanical properties, meets the welding requirements of low-alloy high-strength steel, and can meet the corresponding strength requirements and welding requirements when being particularly applied to welding of weather-resistant bridge steel Q690 qE.

In the case of welding the wires of examples 1 to 8 and comparative examples 1 to 8 to the base material, the spatter during welding and the formation of the weld were observed, and the structures thereof are shown in tables 4 and 5

TABLE 4 weldability of the welding wires of examples 1-8

TABLE 5 weldability of the welding wires of comparative examples 1 to 8

From the above tables 4 and 5, it can be seen that the welding processes of examples 1 to 8 of the present invention are excellent, no spatter is generated during the welding process, and the weld is formed beautifully.

the mass fractions of deposited metals after welding with the welding wires of examples 1 to 8 and comparative examples 1 to 8 were measured, and the results are shown in table 6, and the I values of the deposited metals of examples 1 to 8 were calculated to determine the weather resistance.

TABLE 6 mass fraction and I value of deposited metal

In Table 6, the I value indicates weather resistance of the deposited metal, and the higher the I value, the better the weather resistance of the deposited metal, and the I values of examples 1 to 8 are 9 to 11, wherein the I value of example 1 is 11.72771, and the I value of example 3 is 11.93385, and the weather resistance is excellent.

the deposited metal of example 1 was etched with a 4% nital solution, and then mechanically polished to prepare a metallographic specimen, and the metallographic structure thereof was observed in a metallographic microscope, as shown in fig. 1 and 2, and as can be seen from fig. 1 and 2, the deposited metal was free of defects, and the deposited metal structure was bainite + ferrite.

Claims

1. The utility model provides a supporting gas shielded welding wire of resistant bridge steel Q690qE which characterized in that: the paint comprises the following components in percentage by mass: mn: 1.40% -1.80%; ni: 2.00% -3.00%; mo: 0.30% -0.65%; c is more than 0 and less than or equal to 0.10 percent; si is more than 0 and less than or equal to 0.60 percent; s is more than 0 and less than or equal to 0.010 percent; p is more than 0 and less than or equal to 0.010 percent; cr is more than 0 and less than or equal to 0.60 percent; cu is more than 0 and less than or equal to 0.35 percent; ti is more than 0 and less than or equal to 0.005 percent; v is more than 0 and less than or equal to 0.005 percent; the balance being Fe and other impurities.

2. The weather-resistant bridge steel Q690qE mating gas shielded welding wire of claim 1, wherein: the paint comprises the following components in percentage by mass:

Mn: 1.40 percent; ni: 2.00%%; mo: 0.30 percent; c: 0.10 percent; si: 0.60 percent; s: 0.010%; p: 0.010%; cr: 0.60 percent; cu: 0.35 percent; ti: 0.005 percent; v: 0.005 percent; the balance being Fe and other impurities.

3. The weather-resistant bridge steel Q690qE mating gas shielded welding wire of claim 1, wherein: the paint comprises the following components in percentage by mass:

Mn: 1.80 percent; ni: 3.00 percent; mo: 0.65 percent; c: 0.10 percent; si: 0.60 percent; s: 0.010%; p: 0.010%; cr: 0.60 percent; cu: 0.35 percent; ti: 0.005 percent; v: 0.005 percent; the balance being Fe and other impurities.

4. A deposited metal characterized by: the deposited metal is formed by welding the welding wire and the base metal as described in the claims 1-3, and the deposited metal comprises the following components in percentage by mass: 0.047% -0.086%, Mn: 1.23% -1.71%, Si: 0.26% -0.54%, Ni: 1.65% -2.77%, Mo: 0.27% -0.57%, Ti: 0.0010% -0.0042%, S: 0.003% -0.0085%, P: 0.0026% -0.01%, Cr: 0.36% -0.54%, Cu: 0.102% -0.32%, V: 0.0013 to 0.0048 percent, and the balance of Fe and impurities.

5. A method of preparing a gas-shielded welding wire as defined in any one of claims 1 to 3, comprising the steps of:

(a) preparing a wire rod, and roughly drawing the wire rod;

(c) Carrying out secondary rough drawing on the wire rod processed in the step (b);

(d) And (c) fine drawing the wire rod treated in the step (c), plating copper on the surface, and winding in layers.

6. The method of producing a gas-shielded welding wire according to claim 5, wherein: in the step (a), the diameter of the wire rod after rough drawing is 4.2 mm.

7. the method of producing a gas-shielded welding wire according to claim 5, wherein: the rough drawing and the secondary rough drawing process comprise the steps of coating boron on the surface of the wire rod by adopting boron liquid, drying at the temperature of 150 ℃ and 200 ℃, matching with drawing powder, and drawing for 3-5 times.

8. the method of producing a gas-shielded welding wire according to claim 5, wherein: the annealing treatment process comprises the following steps:

9. The method of producing a gas-shielded welding wire according to claim 8, wherein: in the temperature rising stage and the first cooling stage, nitrogen with the purity of 99.99 percent is introduced at the speed of 3.2-6m 3/h.

10. the method of producing a gas-shielded welding wire according to claim 7, wherein: and annealing treatment is carried out by adopting a well type annealing furnace or a hood type annealing furnace.